Voltage Optimisers

What are Voltage Optimisers?

Typically electricity in the UK is supplied at 242V but most appliances are rated between 217 and 253V. The concept is that if you can reduce the voltage supplied, then there will be reduction in your electricity bill.

Voltage optimisers reduce the voltage received by the home, to take it down to the lower limit of the rating. This can reduce energy use and power demand. Some devices have a fixed voltage adjustment whilst others regulate the voltage automatically. The unit sits between the mains electricity supply and the rest of the circuit.

Do they save energy?

There is much debate as to whether there are significant energy savings to be made for the average domestic consumer, but the technology is clearly of use if you have very large electricity bills e.g. businesses and industries.

In one large-scale pilot, commissioned by VPhase and Scottish and Southern Energy (SSE), the percentage of electrical energy savings seen by the participants in the scheme were 5.2%, while the carbon reduction was estimated as 5.0 tonnes of CO2 per household over the lifetime of the voltage optimiser (36 years). This 5.2% saving has been debated however, and other smaller studies have show less effective results.

In the non-domestic arena, energy savings of up to 15% have been seen, but more commonly the savings are in the region of 10%. The exact savings are determined by the type and relative mix of equipment that consume the power i.e. motors, lighting and heating.

However, even at the 10% savings figure, if a business is spending £50,000 a year on electricity then this represents a saving of £5,000 per year – enough to really impact the bottom line for businesses.

How do Voltage Optimisers affect appliances?

Voltage optimisers affect appliances in various ways:

  • The use of motors is the largest area where voltage optimisers can make savings. It has been shown that less power is drawn on white goods like fridges and freezers, but only a few percent less. The main savings are to be had in industrial and commercial motors.
  • Lighting savings can be made on magnetic ballast or incandescent lighting (because they become slightly dimmer), but there are no savings on LEDs. Converting to LED will save you far more money than any small savings gained by installing a voltage optimiser.
  • Heaters will consume less power using a voltage optimiser, but consequently will produce less heat and therefore no savings are achieved – so in our opinion it is easier to simply turn the thermostat down!

The business case becomes stronger when it emerges that the payback period after installation is typically between 1 to 3 years and 40%. In some areas, grants are even available e.g in Essex’s Low Carbon Business Programme whilst the Carbon Trust offers low-cost financing for energy-efficient technology. The Energy Saving Trust maintains an online database of possible funding sources.

Voltage Optimisers and Solar PV

If you have a solar PV system, your installer may recommend a voltage optimiser. This is because your PV system can ramp up the voltage in your property – this is how the energy is exported to the grid. Unfortunately if it gets too high, the grid could cut you off, because they are obligated to keep the mains voltage below a certain level. The voltage optimiser will help regulate this and ensure you don’t have any difficulties with the generation of electricity.

So are Voltage Optimisers worth it?

Voltage optimisers do make sense – for some properties and businesses where heating isn’t the primary use of electricity and motors predominate. They shouldn’t be installed as a matter of course however, and only where they are deemed to make a real impact on your energy use.

Think we missed something? Do you have a different opinion?

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